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Worth replacing UPS battery?
June 14, 2012 8:37 PM   Subscribe

Is it worth replacing my UPS battery or buying a newer UPS that better fits my need?

I have a APC Back-UPS ES 725 that I inherited from an old job. I use it at home mainly as a surge protector for a desktop, printer, and speaker system. I use my desktop as a home server but other than that, I don't have any real need for a true UPS. However, it is nice to have for piece of mind.

The couple of times I've noticed the power go out, my desktop shut down immediately - I read somewhere that if the UPS is oversized for the loads, it may not charge the battery enough to provide true UPS?

It looks like the battery died yesterday, and I've been toying whether to replace it or just buy a newer UPS or surge protector that better serves my needs. For APC's genuine replacement battery price I can buy a smaller UPS. 3rd party batteries are cheaper, but not by much, and I worry about QA/QC and whether the risk of them catching fire is higher than losing data when the power cuts out.
posted by ccalgreen to Computers & Internet (7 answers total) 2 users marked this as a favorite
 
I bought new batteries from BatterySpec and they’ve been working fine. The batteries are the most significant cost of the units. I’ve been trying to reuse stuff and quit throwing it out though, so I’m often spending nearly new prices on fixing things.
posted by bongo_x at 9:01 PM on June 14, 2012 [1 favorite]


It's only 450W, so I'd just lay the printer and speakers on house power and live with the fact that you might have to wait until after the lightning storm subsides to do your printing and podcast listening.

As for runtime, APC's page for this has a handy run graph toward the bottom of the page. You're definitely beyond 400W with your current setup, so that's why it shuts you down right away.

Batterywise, it's a commodity. There's no margin in returns, and batteries of this kind are kind of a solved problem. Looks like you pay about double for an APC-branded battery, but even $40 is pretty cheap if it indeed only takes one.
posted by rhizome at 10:39 PM on June 14, 2012


I think you should put only the desktop on the UPS, and leave the rest on a different surge protector. Certain peripherals, such as laser printers, may draw large current during heating cycles, thus may overload the protecting circuits; so, that particular load should be plug directly into the outlet, preferably on an outlet that on a different wire from the rest of the systems. Anyway, UPS and surge protection are generally two different functions, so you should consider your need and get the appropriate device.

It's possible that your battery died, but you should also check if the charging and voltage regulation circuitry of the APC is still functional or not, before replacing the battery. A faulty charging circuit may overheat the battery, cause explosion, etc.. or just shorten battery life, as you observed.

Battery catch fires and explode either when over-charged, or when shorted during discharged. UPS usually have lead-sealed battery, so another concern is orientation of the unit (should be place up-right for proper venting, or the battery may vent electrolite and die). Otherwise, I think OEM battery are fine.
posted by curiousZ at 10:47 PM on June 14, 2012


If you can take it apart and get the dimensions of the sealed lead acid AGM battery in it, you can probably find the battery on eBay for $20 to $40. Go search eBay for "AGM battery", select buy it now option only, sort by price. You'll find everything from 12V 2.5Ah fire alarm batteries up to 12V 30Ah batteries. Buy one that is as close in size/spec to the one your UPS contains now.

Basic googling says that your UPS has a rectangular 12V 9Ah battery which is a very common size, you can buy them for about $23.
posted by thewalrus at 12:32 AM on June 15, 2012


UPS usually have lead-sealed battery, so another concern is orientation of the unit (should be place up-right for proper venting, or the battery may vent electrolite and die).

AGM batteries which are totally sealed can be installed in any orientation, they only vent through and emergency valve if they are significantly overcharged/overheated.
posted by thewalrus at 12:33 AM on June 15, 2012


The couple of times I've noticed the power go out, my desktop shut down immediately
...
It looks like the battery died yesterday

Sounds to me like something was already long-dead. Could you provide more detail about what changed yesterday? I assume it started beeping a lot.

I read somewhere that if the UPS is oversized for the loads, it may not charge the battery enough to provide true UPS?

Nope. The charger is independent of any load. And when power fails, the inverter should kick in to supply AC unless it's overloaded. Underload just means it loafs along happily.

Stupid question: Are you sure you had your desktop plugged into the "battery backup plus surge protection" outlets, and not the "surge protection only" ones? Because that would produce exactly the symptom you describe all along, even with a healthy battery, assuming that the beepy-end-of-battery-lifespan alarm just came in yesterday.
posted by Myself at 10:46 AM on June 15, 2012 [1 favorite]


How old is the UPS? If it's 4 years or more, the battery probably won't hold a charge, as that should be more than enough to handle that load for at least a few minutes. Double check that you didn't accidentally plug the computer into the surge only side, like Myself said - I've seen plenty of smart people do that. I would also put the printer in the surge only side because it's not a mission critical thing and uses up a bunch of power.

If you just want to replace the battery cheaply, go to ebay, search for apc Back-UPS ES 725 battery and pay a fraction of the cost of a new UPS. They are pretty much generic and universal replacement batteries. I replace quite a few of these.

I would suggest investing around $100 in one with LCD readout to see load, life and voltage. I did the same as you, the battery died on a really nice UPS at a client and they didn't want to wait for a replacement battery so they gave it to me (I went to Smoffice Smepot and bought them a new $125 one). eBay found me a new battery for $25 shipped and now I have a beautiful UPS with LCD screen and all the bells and whistles for roughly 20% of what it would have cost brand new. 2 years and counting.
posted by dozo at 1:12 PM on June 15, 2012


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